Ignition control



Aug. 28, 1951 J. S. NEWMAN ET AL IGNITION CONTROL Filed July 25, 1949 5 5 w (/WY m3 m; in Ewe 0 My w J. A a a B Patented Aug. 28, 1951 IGNITION CONTROL John S. Newman, Harnden, Conn., and Kenneth L. Berninger, Dayton, Ohio, assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application July 23, 1949, Serial No. 106,462

This invention relates to spark ignition control for internal combustion engines, and has for an object in general to save the engine from injury due to abnormal operation.

An object of the invention is to provide a system of control, such as stopping an engine with which it is installed or incorporated should the lubrication oil pressure fall below a predetermined value, the coolant temperature rise above a predetermined value, and/ or the coolant system pressure rise above a predetermined value.

A further object of the invention is to provide a control system of the class described and so designed that no additional manipulations are required to start and operate the engine on which the control system is installed.

A further object of the invention is to provide a control system that will give adequate warning before a damaging condition obtains, and incorporates a means for bypassing the automatic stopping in the case of emergency, such that the engine and the operator will not be left in a critical condition without some means of rectifying the condition.

One of the most important objects of the invention is to provide a guarded ignition circuit for an internal combustion engine that becomes complete only after the engine becomes self-operative and then contains a plurality of interruptable points guarding the normal operation of the engine, the interruption of any one of which will effect the stopping of the engine before any damaging effects can materialize, there being a detectable by-pass for the interruptab-le points for emergency operation of the engine, and a cyclically operated by-pass for setting up a temporary circuit by which the engine can be made self-operative before all of the guard points are properly conditioned by self-operation of the engine.

A corresponding object of the invention is to provide a Work circuit for an electrical device with a plurality of guard devices including a pair of normally open switches, and one of which is closed only after the device becomes self-operative by reason of current flowing through the work circuit, and in which a cycling by-pass circuit makes it possible to operate the device long enough for all the guard points to be so conditioned as to complete the work circuit.

A further object of the invention is to provide a guarded work circuit with a detectable by-pass therefore whereby, operation of any of the guard devices to interrupt the work circuit may be detected at a subsequent time.

A further object of the invention is to provide 10 Claims. (01. 29038) a guarded work circuit with normally open contact points which are closed only on full manifestation of the work device, with a time controlled by-pass efiective to effect energization of the work device for sufficient time that the normally open contact points may be closed.

As applied specifically, it is an object of the invention to provide fleet operators of taxis, trucks, buses and the like with means for protecting their investment in equipmentbysafeguarding the operation of their equipment under conditions of maloperation, and providing the owners with an indication that an attempt has been made to operate the equipment under abnormal conditions endangering the engine.

Likewise a further object of the invention is to provide fleet operators of vehicles with guarded control of their ignition circuits and a time controlled shunt around the guard points so that the engines may be started and the guard circuits set up, the time element of the shunt being such that it will be shorter than the time required for an engine running under malconditions to damage itself.

Yet a further object of the invention is to provide a guarded engine ignition circuit in which the battery is safe-guarded against drain should the circuit be left with the ignition control switch in circuit closed position.

Among other objects is to provide an engine ignition guard circuit with an automatic time delay shunt relay to insure the operator or owner of the engine of its being properly set without introducing a special manual operation because of the installation of the device, thereby eliminating the human element.

It is intended that the improvements shall apply to internal combustion engines whether they be of the mobile type or of the stationary type, and whether or not they be constantly attended by an operator. With respect to mobile installations, such as passenger vehicles, commercial transport trucks, buses, boats, aircraft and the like, the attendant is given a warning at the approach of the endangering conditions, so that he can get out of a hazardous situation, by resorting to the detectable by-pass. It should be apparent that the driver of a mobile installation is given much relief in his driving activities where the conditions are such that all of his attention should be given to the control of the vehicle, such as in heavy traflic, crooked, winding and hilly highways, heavy weather and the like. The driver can devote all of his time to the control of the Vehicle, without being forced to keep track of several gauges and instrument dials, with the possibility of misreading one or more of them during a fleeting glance, or because of poor illumination of the instrument dials. The driver need give no attention to the engine operation until one of the guard devices effects an opening in the ignition circuit, and then he has but to rupture the frangible element and close the laypass long enough to get out of a hazardous situation if such exists. Stationary installations are not always attended constantly, and therefore where the internal combustion engine drives air compressors, electric arc welders, water pumps, auxiliary or principal electric power generators, and many other like devices, the approach of maloperations will be detected early in the occurrence and the engine rendered-inoperative before "any serious damage results. The invention is particularly valuable here where there is no attendant to keep watch of the various dials and gauges.

The importance, magnitude and d-ifiiculty in accomplishing the foregoing objects can be lappreciated when it is considered that a fleet owner of a line of trucks or taxicabs is; faced with the problem of protecting hisv expensive equipment against the damage wrought by heedless drivers. The drivers are paid topilot the vehicle from point to point, and usually give no thought to the efficiency or proper operation of the engines, If an engine malfunctions for Want of oil or water, that is just too bad, and they may push the equipment on to the limit, it being nothing out of theirpocket. Hence the vehicle may be driven on until it will go no further, resulting in a burned out motor, andperhaps the destruction of the entire vehicle and its load. Stopping of the vehicle engine purposely on the first occur rence of malfunctioning conditions will usually save the loss and even prevent serious damage to the engine. I The improvements herein disclosed accomplish that saving by providing a guard circuit for the primary ignition circuit of the engine, with a plurality of guard points, any of which may effect the stopping of the engine for want of sufficient lubrication oil pressure or unduly hot radiator or other engine cooling device. At least one of these guard points is a switch that is normally open during the quiescent period of the engine but becomes closed so as to complete the primary ignition circuit when the engine becomes selfoperative. A timed or cycling circuit is incorporated to shunt the normally open guard device during the starting period and is energized coincidentally with the starting motor circuit so that energy may be conveyed to the essential parts of the engine despite the fact that one of the guard points in the standard circuit is open. The timed "circuit is characterized such that it will remain brication system or the engine cooling system that the guard devices would stop the engine, damage to the equipment is prevented. In order to afford continued operation of the engine so that the faultyequipment may be moved to a garage under its own power, or to the side of the road for parking, or out of a hardardous situation as a busy intersection, or from an obstructing position on a hill, a detectable shunt is provided that by-'-passes all of the guard devices so that the engine can be operated without further interruptions. The detectable shunt is so called b cause of the fact that it can not be closed without being detected for some time after. Its control switch is housed Within a chamber sealed with an easily frangible cover while the switch points are/held open. Thus, the garage attendant of the fleet, in checking the vehicles for the road, notes the condition of the frangible element. If itis ruptured, he knows that there has been some trouble With the engine and he is put on warning that the engine cooling system and engine lubricating system should be carefully checked even though not reported by the driver. One fea-= ture of the timed or cycling circuit is its ability to maintain itself throughout the measured time interval, and itsv ability to maintain the initial shunt around the guarded devices for the meas- Lu'edtime interval though the initial energizing circuit is broken with the disconnection of the starting motor.

For a better andmore complete understanding of the invention reference is now made, to the drawings, wherein the single figure illustrates a circuit diagram for connecting the various devices in practicing the invention.

Referring specifically to the drawing, It refers to the usual storage battery of an engine ignition system, having a ground connection at l2 and a conductor I l supplying the batter current to an ignition circuit which is controlled as to its off and on condition by the usual ignition switch I6. The switch l6 determines whether or not current will flow as intended through an ignition coil [8 and a circuit breaker or timer 2i) to produce high tension current in the lead 242? to be distributed by the distributor i i to the spark plugs 26. In the conventional installation, the circuit connections between the terminal 28 of the ignition switch [6 and the terminal post 30. of the coil l8 are more or less continuous and uninterrupted, but in the present instance is completed by a series, of interruptible contact devices whose condition is controlled by guard devices in response to particular manifestations of engine running conditions. Responding to the conditions of proper lubrication oil, and the fluid pressure with which it is delivered to the bearing surfaces of the engine, is the guard device 32 consisting of a pair of contacts, 34, 3.6 normally in open circuit relation but which may be closed by a bridging member 38 supported by a flexible diaphragm 46 from the edge of a chamber 42,, there being a tubular connection 64 connecting the chamber to. the oil pressure line designed to lubricate the engine bearings. When the engine oil is delivered at a pressure that is safe enough to maintain proper lubrication, the diaphragm. 40 will be deflected sufficiently that the bridging member 38 will connect the contacts 34, 36, the contact 3 being connected to the ignition switch by a conductor 46, while the contact 36 is'connected by lead 48 to a thermal element 50' constituting a second guard device in the ignition circuit.

The thermal element 5.0 is preferably of bimetal construction and ri idly supported at one end 52 with the other end carrying a contact 54 normally engaging a fixed contact 56 connected by a lead 58 to a contact of a third guard device 60. The guard device 60 includes a pair of contacts 62, 64 normally connected by a bridgin member 66 actuatable to open condition by a movable element 6'! of a pressure responsive bellows '68, the contact 6tv being connected by lead 69 with a relay I at the point I2. Both of the guard devices 50 and 60 are responsive to conditions of the engine cooling system in that the guard device 50 is immersed in or otherwise exposed to the cooling medium temperature, and upon its rise to an abnormal value flexes to open the contacts 54, 56, while the guard device 60 is immersed in or otherwise exposed to the cooling medium pressure, and upon rise of the pressure to an abnormal value moves the member 66 to open the contacts 62, 64. The relay I0 includes an armature I4 carrying a contact I6 adapted to engage a fixed contact 11 connected with a holding coil I8 of the relay, which coil in turn is connected by lead I9 to the terminal post 30 of the ignition coil I8. Thus, a guarded ignition circuit extends from th battery I0 to the ignition device for the engine, and includes between the ignition switch and the coil, an oil pressure switch 32 having normally open contacts, a coolant temperature switch 50 with normally closed contacts, a coolant pressure switch 60 having normally closed contacts, and a relay controlled switch 10 having normally open contacts. When the engine is operating, th interruption of any one of these sets of contacts will cause the engine to stop operating. In the quiescent stage of the engine, the sets of contacts 34, 36 for the oil pressure switch and I6, 11 for the relay are normally open. Both sets of normally open contacts must be closed or bridged before the ignition device can be energized so as to make the engine operative. The oil pressure switch 32 does not close until the engine becomes operative enough to drive its lubricating pump and supply oil under pressure, and the contacts of relay I0 do not close until the armature I4 is actuated. Therefore, a time controlled or cycling by-pass is provided for the oil pressure switch, and an actuating means is provided for the relay contacts.

A starting motor circuit extends from the battery I0 by way of a conductor II joining a contact I3, a second contact I being connected with a starting motor I! grounded at I2. Disposed to bridge the contacts I3 and I5 there is the member I9 actuated by a core member 2I immersed in the field of a solenoid windin 23 grounded on the starting motor I1 and connectible by a starting switch 25 with the conductor I4 through a lead 21. It will be appreciated that closing of the switch 25 will energize the solenoid 23 and eifect closing of the contacts I3 and I5, which energizes the starting motor IT to crank the engine. From the contact I5 a lead 29 extends to a double contact solenoid actuated relay 80 having a pair of contacts 82, 84 normally closed by a bar 86 carried by the movable member 88 of a solenoid switch. and having a bar 80 adapted to close a pair of contacts 92, 94. A connection 96 joins the contacts 84, 94 and is connected by a lead 98 with an electric timing or cycling motor I 00 grounded at I2, while an extension or branch I02 from 98 communicates with an actuating windin I04 of the relay and has its ground at I2. The end of the shaft I06 of the motor I00 ends in a small pinion I08 meshing with a large gear IIO (representing a suitable gear reduction), on a shaft I I2 driving a pair of cams H4 and I I6. The high points of these cams each engage a spring leaf, or spring urged leaf H8 and I respectively and normally, that is, while at rest, hold movable contacts I22, I24 out of engagement with the fixed .contacts I26, I28, their closing when the cams rotate being assisted by springs I30. The leaves I20 and H8 are connected together by a wire I32 and are joined to a lead I 34 connected to point I2 of the relay I0. To the contact I26 is joined a lead I36 connecting to contact 92 and extending by part I31 to an energizing winding I38 in turn grounded at I2. Finally, to the contact I28 there is joined a wire I40 leading back to the contact 34 of the oil pressure switch 32.

It will be observed that the wire I40, contacts I28, I24, leaf I20 and wires I32, I34 to the point I2, and constitute a by-pass circuit around the normally open contacts 34, 35 of the guard device 32 when the cam controlled points I24, I28 are allowed to close by rotation of the cam H6. That is the time controlled or cycling by-pass heretofore mentioned. Rotation of the cam H6, as is also rotation of the cam H4, is effected by the timing motor I00 and gear reduction I08, H0. The motor I00 is first energized upon closing of the starting motor contacts I3, I5 which connects lead 29 with the battery I0 and with the motor I00 through the contacts 82, 84, bridging bar 86, lead 96 and wire 98 to ground at I 2. The timing motor in running drives the cams I I4, H6 and so lowers their crests that the contacts I 22, I24 close two circuits through the contacts I26, I28 as will presently be explained. Coincident with closing the circuit through the time motor I00 the actuating winding I04 of the relay I0 is also energized which draws down the armature 14 to close the contacts I6, 11 such that there is then but one guard point open at the oil pressure switch 32. The two circuits closed by the motor I00 driving the cams are first the by-pass circuit including the wire I40 from the contact 34 through the contacts I24, I28 and lead I 34 to the armature I4, and which since the contacts 16, 11 are in closed condition because of the energy in actuating winding I04, completes the temporary ignition circuit through the by-pass, and second, a circuit to energize the solenoid and shift the energizing circuit for the time motor I 00. Closing of the contacts I22, I26 energizes the winding I38 of the solenoid relay 80 and actuates the member 88 to shift the bars 86, 90. That opens the circuit through elements 82, 84, 86 and closes the contacts 92, 94 so that the lead 98 to the motor I00 is now energized through I36, contacts I26, I22, leaf II8, branch I32, leaf I 20, contacts I24, I28 and wire I40. Thus, the timing motor I00, when it is energized, completes the by-pass circuit around the guard elements, and shifts or transfers th feed line for the timing motor from the terminal I5 of the starting motor to the terminal 34 of the oil pressure switch.

The timing motor I00 with its gear reduction I08, IIO to the cams H4, H6 operates through a definite period of time or over a definite cycle, which in this instance is set for three minutes. During that time, the engine should have become self-operative through the by-pass circuit. As soon as the engine becomes self-operative, the guard device 32 should close the contacts 34, 36 and there-by establish the desired ignition circuit traversing all of the guard devices. In substance, only a singe short closing of the switch 25 is needed to start the timing or cycling motor I00 on its cycling operation, for as soon as the motor I00 starts it operates to close the cam operated contacts I22, I26 which effects a change-over of its energy supply from the battery lead II to the ignition lead I4. Hence, though the starting motor circuit may be closed for only a second or more, the circuit to and through the timing motor I00 continues to the end of the cycle for 7 which it is designed to run, in the suggested example, three minutes; During that interval, the cams H4 and I IE will have made one complete revolution and bring the risers thereof to the illustrated position which actuates both leaves -I I8 and I to open their respectively associated contacts. Opening of the contacts I22, I26 interrupts the circuit to the motor I00, and opening of the contacts I24, I28 interrupts the by-pass circuit around the guard devices 32, 50 and 60. Within the three minute time intervals, if the conditions are normal, the engine should have been made. self -operative, even though it necessitated repeated closings of the starting motor circuit. If the conditions are normal, comp-rehends that the lubricating system is. operating properly to provide the designed amount of oil under a suitable pressure, and that the. coolant system is satisfactory as to temperature and pressure. If one or the other of them are at fault, the respective guard device will operate to open the respective pair of contacts in the guarded ignition circuit, and hence, at the end of the cycled operation of the motor I00, if those malconditions exist at the time of cranking, will r operate to stop the faulty engine, unless the starting motor switch is again closed for recycling the timing motor I00 on a successive three minute run. It is now, of course, obvious that engine running conditions during a long and laborious haul of a heavy load, or other operating condition that taxes the endurance or efiiciency of an engine may likewise cause a deficiency of lubricating oil pressure, or a depletion of the coolant for the engine that its temperature or pressure deviates from the prescribed range, manifesting in the opening of the respective pair of contacts in the guarded ignition circuit. When that occurs the engine will stop, as has been explained. Preferably, the guard devices are so calibrated that their opening of the respective contacts will be as near the low point on the respective scale of danger as possible, so that their opening is well above the designed safe range but low enough that they will open before any real damage to the engine occurs. Thus, manifestation of bad conditions by any of the guard devices gives a warning that the equipment should be checked for faults.

Since it is conceivable that the guard devices may open the ignition circuit and leave the vehicle in an embarrassing or hazardous situation, from which, by necessity or desire it would be Wise to move the vehicle, an interruptable by-pass circuit is provided by which the driver can circumvent all of the sets of separable contacts in the ignition circuit, between the usual ignition switch I6 and the coil I8. That bypass embraces a lead I42 joined to the contact 34 of the oil pressure switch and which connects with a spring leaf or like element I 44 Within a sealed receptacle I40. The element I44 carries a contact I48 adapted to, engage a fixed contact I50 connected by a wire I52 with the conductor 19 leading to the ignition coil terminal 30. The element I44 is normally held in depressed position by means of a lever I54 pivoted within the I54 to permit the contacts I48 andto close. The parts are so designed that merely breaking the frangible element I58 will eilect closing of the detectable .by-pass circuit. This is because the spring element I 44, which engages the enlarged portion of the lever I54, moves the lever in a counterclockwise direction, as viewed in the drawing, until the contact I48 engages contact I50. At any event, the closing of the contacts I48, I50 establishes a complete electrical connecti-on between the ignition switch I0 and the ignition coil I5, with the result that the engine can now be operated despite the guard devices so long as the conditions of the lubricating system and coolant system will permit. That should be long enough to permit the driver to maneuver the vehicle out of a hazardous position, a busy intersection, to a suitable parking place, or to a garage or service station where the faulty condition of the engine might be remedied. However, the fact that there has been malfunctioning of the equipment is evidenced by the ruptured cover of the sealed casing, and Will be observed by the fleet manager or attendant at the home garage. He is thereby put on notice to give special attention to the equipment and remedy the cause. After that is done he adjusts the contacts I48, I50 to the open condition and renews the frangible element I58.

While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. A guarded ignition circuit for an internal combustion engine, comprising in combination, a plurality of separable contacts in series adapted to be actuated by guard devices responding to engine operating conditions, including at least one pair of contacts normally open and closeable only upon the engine becoming self-operative, means for cranking the engine for starting, and a time controlled by-pass extending around all of the guard devices for temporarily completing the ignition circuit when the engine is being cranked.

2. A guarded ignition circuit for an internal combustion engine, comprising in combination, a plurality of separable contacts in series adapted to be actuated by guard devices responding to engine operating conditions, including at least one pair of contacts normally open and closeable only upon the engine becoming self-operative, means for cranking the engine for starting, a bypass circuit adapted to be closed for temporarily closing the ignition circuit means coincidentally operable with the cranking motor for closing the by-pass circuit during a predetermined interval of time.

3. A guarded ignition circuit for an. internal combustion engine, comprising in combination, a plurality of separable contacts in series adapted to be actuated by guard devices responding to engine operating conditions, including at least one pair of contacts normally open and closeable only upon the engine becoming self-operative, means for cranking the engine for starting, a by-pass circuit extending around all of the separable contacts actuatable by the guard devices for temporarily completing the ignition circuit, time controlled means energized coincidentally with the energization of the cranking motor for measuring the interval of time that the by-pass circuit is maintained closed.

4. The combination set forth in claim 3 wherein the time controlled means comprises a motor and gear reduction for driving a pair of switch operating cams, one of which effects transfer of energy from the cranking motor circuit to the said by-pass circuit and effects its own secession at the end of a measured time interval.

5. An ignition circuit for an internal combustion engine, comprising in combination, a. plurality of sets of contacts in series between a current source and the ignition devices for said engine, a plurality of guard devices responding to different phenomena of engine operation for actuating said contacts, at least one set of contacts being normally open during quiescent conditions of said engine but closed by satisfactory self-operation of said engine, and the opening of any one set of contacts while the engine is operating effecting the opening of the ignition circuit, a by-pass circuit with separable contacts connected around all of said guard actuated contacts, means incident to cranking of the engine for closing the contacts in the by-pass circuit, said means including a motor and solenoid switch with electrical connections to the current source for measuring the interval of continued closing of said by-pass circuit contacts.

6. An ignition circuit for an internal combustion engine, comprising in combination, a plurality of sets of contacts in series between a current source and the ignition devices for said engine, a plurality of guard devices responding to different malfunctioning conditions of said engine for opening the respective set of contacts to stop the engine, one set of contacts being normally open when the engine is not operating but closed by satisfactory self-operation of said engine, a bypass circuit extending around the sets of contacts for all guard devices adapted for temporarily completing the ignition circuit during engine cranking conditions, cycling means determining the period of time the by-pass circuit remains closed, and a detectable by-pass circumventing all of the sets of contacts whereby the ignition circuit to the engine may be completed despite the condition of the guard devices.

7. The combination set forth in claim 6, wherein the detectable by-pass includes a pair of switch contacts maintained in open circuit condition by an easily frangible element so that the said detectable by-pass circuit may not be closed except that a continuing indication of the fact be given.

8. A guarded ignition circuit for an internal combustion engine, comprising in combination, a plurality of separable contacts adapted to be actuated by guard devices responding to engine operating conditions, including at least one pair of contacts normally open and closeable only when the engine becomes satisfactorily self-operative; means for cranking the engine for starting; a time controlled by-pass circuit extending around all of the guard devices for temporarily completing the ignition circuit when the engine is being cranked; and means coincidentally operable with the cranking means for closing the by-pass circuit during a predetermined interval of time.

9. In an ignition circuit for internal combustion engines comprising in combination; a current source; a plurality of sets of contacts connected between the source and the ignition devices of the engine, one set of which is normally open but is closed by satisfactory selfoperation of the engine, guard devices for guarding the operation of said engine by opening a set of contacts in response to malfunctioning of the engine; a by-pass circuit for temporarily shunting said normally open set of contacts whereby the ignition circuit is temporarily completed during cranking of the engine; time controlled means for measuring the time period that the by-pass circuit may remain closed; and a detectable by-pass for circumventing all of the sets of contacts controlled by the guard devices.

10. A guarded ignition circuit for an internal combustion engine comprising in combination; a battery; a starting motor circuit; an ignition circuit including the battery and a plurality of sets of contacts, said sets of contacts adapted to be actuated by guard devices responding to different malfunctioning conditions of the engine for opening the respective sets of contacts to open the ignition circuit, one set of contacts being normally open when the engine is idle but closed by satisfactory self-operation of the engine; a by-pass circuit about the sets of contacts for all the guard devices adapted for temporarily completing the ignition circuit coincidentally with the closing of the starting circuit; time controlled means energized coincidentally with the closing of starting circuit 'for maintaining the by-pass circuit closed for a predetermined length of time; and a second by-pass circuit adapted to be connected with the battery to complete the ignition circuit in case one of the guard devices does not function to maintain the ignition circuit energized.

JOHN S. NEWMAN. KENNETH L. BERNINGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,298,728 Jackson Apr. 1, 1919 1,654,220 Johnstone et a1 Dec. 27, 1927 1,770,264 Eslinger July 8, 1930 1,854,571 Albertson Apr. 19, 1932 2,162,174 Jones June 13, 1939 2,166,498 Lacey July 18, 1939 2,337,838 Reavis Dec. 28, 1943 2,463,470 Sherwood Mar. 1, 1947 FOREIGN PATENTS Number Country Date 765,717 France Mar. 26, 1934 

